Type species: Veretillum cynomorium (Pallas, 1766)
Total number of species estimated: 3
Description: Cylindrical or slightly clavate. Axis variable: from well-developed to absent. Polyps radially arranged throughout the rachis. Polyps emanate directly from surface of rachis. Polyp leaves absent. Polyps retractile into rachis withoput polyp calyces. Siphonozooids numerous between autozooids, sometimes in longitudinal rows. Sclerites are small irregularly-shaped plates with sparse denticulation or tuberculation; bone- or bisquit-shaped plates also present. Sclerites may be absent from the rachis altogether. Deep interior of the peduncle contains numerous minute otolith-like avals. Polyp sclerites present or absent. Zoozanthellae not reported.
Habitat: Shallow water sandy areas in and around rock or coral reefs, also in deeper water.
Range: Eastern Atlantic and Indo-West Pacific (southern europe and Mediterranean Sea, along west coast of Africa, and from southern Mozambique to the Philippines and New Guinea); 6-220 meters in depth. The highest diversity of species is in the tropical western Pacific.
Ecology: Some species, notably Veretillum cynomorium and V. manillense , are known to produce a brilliant green bioluminescense, presumably to startle potential predators.
Additional remarks: Policella Gray, 1870 is considered a synonym of Veretillum by Williams, 1995. Bioactive compound known as malayenolides (oxygenated briarane diterpenes) have recently been discovered in Veretillum malayense Hickson, 1916 from Indonesia (see: Fu et al., 1999).